Fuel-injection means and method



Mair. 1929. E, vo s ls 1,703,913

FUEL INJEQTION mmns AND METHOD Filed May 3, 1926 Patented Mar. 5, 1929,

untrue STATES.

EDUARID voN SALIS, OF WINTERTHU R, SWITZERLAND, ASSIGNOR T BUSOH-SULZERBROS-DIESEL ENGINE COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OFMISSOURI.

Application filed May 3, 1926, Serial No.

v The invention relates to injection type internal combustion engineshaving accumulators in their fuel lines and its object is to improve thegeneral eiliciency of this type of engine as below made apparent. Tothis end, the invention consists broadly in controlling the pressureexerted by the accumulator, un-

der variations of the volume of the injection fuel charge, so that suchpressure is high to enough for the minimum fuel pharge and not muchhigher for. the maximumcharge. In this way the fuel pumps are calledupon to y do little or no more workwhen under full load or overload thanwhen the engine is idling and with a corresponding saving of energy aswell as economy of structure, the injection velocity being adequatelyhigh for both conditions. The control referred to can be accomplishedmanually or automatically, 2 and when accomplished automatically, by avariet of mechanical embodiments not great 1y difiering in generalstructure from existing accumulators and hence easily accommodated toexisting power plants. ln the drawing Fig. l diagrammatically representsan example of one automatic embodiment of the invention.

Fig. 2, another, and 3 illustrates the apparatus in which the method canbe manually performed.

Referring to Fig. 1: The fuel is delivered by a variable delivery fuelpump 1 diagrammatically shown but understood to be driven by the engineand controlled by hand or by governor in the usual way. The fuel isforced by thepump, through pipe 2, to the accumulator cylinder 3 andthence by pipe a to the injector or spray valve 5, which is of a knowntype in which the pressure of the fuel opens the injection passage aswill be understood from the diagram.

The accumulator consists essentially of a spring-pressed plunger 6 asusual but the spring acts on a cross-head 7 which moves in its housing 8transverely or at. an angle to the plunger axis, being connected to itby means of a thrust-link 9. The efiect of this relative arrangement ofplunger and spring is that on a small fuel charge, delivered by thepump, with correspondingly small displacement of the accumulatorplunger, the link has a less favorable angle for compressing the spring,and on larger fuel charge and great- FUEL-TNJECTION MEANS AND METHOD.

106,272, and in Switzerland July 1, 1925.

er displacement of plunger 6, it has a more favorable angle. Thereby thepressure exert-. ed by the spring on the accumulator plunger is greaterthan proportional to the volume of the charge atv low load (charge) andless than roportional to the volume at high load char e) than it ylouldbe if the spring acted directly on the plunger, as in the usualarrangement. In other words, the accumulator pressure increases at aless rate than the volume of fuel charge increases. Desirably, theaccumulator pressure increase could be zero, at least above a certainminimum pressure adequate for producing proper injection velocity forthe smallest fuel charge. It will be obvious to those skilled in thisart that the rate 'of pressure increase can be controlled variously.

The variation of such pressure can also be accomplished in steps orstages, if desired, and within this invention, as illustrated in Fig. 2,wherein small fuel charges displace the accumulator plunger 10 bycorresponding amounts up to the point where the plunger uncovers port11. For such small displacements, the'accumulator pressure and the fuelvolume will vary together and uniformly, according to thecharacteristics of the spring employed. When the port 11 is uncoveredthe I resilience of an auxiliary accumulator device diagrammatically reresented by 11 is brought into play re ucing the pressure on the fuel.This auxiliary device may be an air chamber or another accumulatorspring as will be understood. In like manner, the rate of change of theaccumulator pressure can be accomplished in more than two stages.

In Fig. 3, three or more accumulator devices, marked 13, 14 and 15respectively, are connected in or to the fuel line and are intended tobe successively opened to the line as by manipulation of the valves 16and 17, accord ing as the volume of the fuel charge is varied bymanipulation of the control handle on the variable delivery pump. Forthe smaller charges, only the accumulator 13 will be active; for mediumcharge the accumulators l3 and It will be active, and for full loadcharges, all three of them.

Having described the invention, the following is claimed:

1. In injection type engines the combination with the fuel pump and fuelinjector, of a plurality of resilient accumulator means, and means forbringing them successively into action.

2. The method of controlling the fuel supply of injection type engineshaving fuel accumulators, which consists in relieving thepressure-increasing resistance which the accumulator offers in responseto increase in the volume of the fuel charge, whereby the accumulatorpressure increases at a rate less than proportional to the rate ofincrease of the volume of the fuel charge.

3. The method of controlling the fuel supply of injection type engineshaving fuel accumulators, which consists in increasing the EDUARD VONSALTS.

